Arrangements for an integrated sensor

ABSTRACT

An integrated circuit can have a first substrate supporting a magnetic field sensing element and a second substrate supporting another magnetic field sensing element. The first and second substrates can be arranged in a variety of configurations. Another integrated circuit can have a first magnetic field sensing element and second different magnetic field sensing element disposed on surfaces thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application a Divisional Application of and claims the benefit ofU.S. patent application Ser. No. 12/792,245 filed Jun. 2, 2010, which isa Divisional Application of and claims the benefit of U.S. patentapplication Ser. No. 11/335,944 filed on Jan. 20, 2006, both of whichapplications are incorporated herein by reference herein in theirentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

FIELD OF THE INVENTION

This invention relates generally to integrated circuits and, moreparticularly, to integrated circuits having magnetic sensing elements.

BACKGROUND OF THE INVENTION

As is known in the art, one type of conventional current sensor uses aHall effect element, which generates a voltage in response to a magneticfield associated with a current passing through a conductor. Typicalcurrent sensors of this type include a Hall effect elements mounted on adielectric material, for example a circuit board. Typically, a ferrouscore (flux concentrator) is used in proximity to the Hall effectelement.

Another type of conventional current sensor uses a magnetoresistanceelement, which changes resistance in response to a magnetic fieldassociated with a current passing through a conductor. A fixedelectrical current is directed through the magnetoresistance element,thereby generating a voltage output signal proportional to the magneticfield. Conventional current sensors of this type use an anisotropicmagnetoresistance (AMR) element mounted on a dielectric material, forexample a circuit board.

Various parameters characterize the performance of current sensors,including sensitivity and linearity. Sensitivity is related to a changein the resistance of the magnetoresistance element or a change in outputvoltage from the Hall effect element in response to a change in magneticfield. Linearity is related to the degree to which the resistance of themagnetoresistance element or the output voltage from the Hall effectelement varies in direct linear proportion to the magnetic field.

Various types of magnetic field sensing elements (e.g., Hall effectelements and magnetoresistance elements) are known to have differentcharacteristics, including, but not limited to, different sensitivities,different linearities, and also different hysteresis characteristics inresponse to a magnetic field. It is also known that a particular type ofmagnetic field sensing element, for example, a Hall effect element, canhave a substantially different sensitivity when fabricated on substratescomprised of different materials, for example, Silicon (Si) and GalliumArsenide (GaAs).

Typical current sensors tend to be undesirably large, both in terms ofheight and circuit board area. Typical current sensors also tend to berestricted in dynamic range, i.e., they tend to saturate at largecurrents, which generate large magnetic fields, and/or they tend to beinaccurate at small sensed currents, which generate small magneticfields. It would, therefore, be desirable to provide a current sensorhaving a reduced size, improved accuracy, and/or improved dynamic range.

While conventional current sensors are described above as havingparticular disadvantages, it will be appreciated that conventionalexternal magnetic field sensors and also conventional electrical signalisolators suffer from the same disadvantages. It would, therefore, bedesirable to provide an external magnetic field sensor and also anelectrical signal isolator having a reduced size, improved accuracy,and/or improved dynamic range.

SUMMARY OF THE INVENTION

In accordance with the present invention, an integrated circuit includesa lead frame and a first substrate having first and second opposingsurfaces. The first substrate is coupled to the lead frame. Theintegrated circuit also includes a second substrate having first andsecond opposing surfaces. The first substrate and the second substrateare coupled such that the first surface of the second substrate isproximate to the first surface of the first substrate and the secondsurface of the second substrate is distal from the second surface of thesecond substrate. The integrated circuit also includes an electroniccomponent disposed on the first surface of the first substrate and amagnetic field sensing element disposed on the first surface of thesecond substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes a lead frame and a first substrate havingfirst and second opposing surfaces. The first substrate is coupled tothe lead frame such that the second surface of the first substrate isabove the lead frame and the first surface of the first substrate isabove the second surface of the first substrate. The integrated circuitalso includes a second substrate having first and second opposingsurfaces. The first substrate and the second substrate are coupled suchthat the second surface of the second surface is above the first surfaceof the first substrate and the first surface of the second substrate isabove the second surface of the second substrate. The integrated circuitalso includes an electronic component disposed on the first surface ofthe first substrate and a magnetic field sensing element disposed on thefirst surface of the second substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes a lead frame and a first substrate havingfirst and second opposing surfaces. The first substrate is coupled tothe lead frame such that the second surface of the first substrate isabove the lead frame and the first surface of the first substrate isabove the second surface of the first substrate. The integrated circuitalso includes a second substrate having first and second opposingsurfaces. The second substrate is coupled to the lead frame such thatthe second surface of the second substrate is above the lead frame andthe first surface of the second substrate is above the second surface ofthe second substrate. The integrated circuit also includes an electroniccomponent disposed on the first surface of the first substrate. Theintegrated circuit also includes a first magnetic field sensing elementdisposed on the first surface of the second substrate and a secondmagnetic field sensing element disposed on the first surface of thefirst substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes a lead frame and a base substrate havingfirst and second opposing surfaces. The base substrate is coupled to thelead frame such that the second surface of the base substrate is abovethe lead frame and the first surface of the base substrate is above thesecond surface of the base substrate. The integrated circuit alsoincludes a first substrate having first and second opposing surfaces.The first substrate is coupled to the base substrate such that the firstsurface of the first substrate is above the first surface of the basesubstrate and the second surface of the first substrate is above thefirst surface of the first substrate. The integrated circuit alsoincludes a second substrate having first and second opposing surfaces.The second substrate is coupled to the base substrate such that thefirst surface of the second substrate is above the first surface of thebase substrate and the second surface of the second substrate is abovethe first surface of the second substrate. The integrated circuit alsoincludes an electronic component disposed on the first surface of thefirst substrate and a magnetic field sensing element disposed on thefirst surface of the second substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes a lead frame and a base substrate havingfirst and second opposing surfaces. The base substrate is coupled to thelead frame such that the second surface of the base substrate is abovethe lead frame and the first surface of the base substrate is above thesecond surface of the base substrate. The integrated circuit alsoincludes a first substrate having first and second opposing surfaces.The first substrate is coupled to the base substrate such that thesecond surface of the first substrate is above the first surface of thebase substrate and the first surface of the first substrate is above thesecond surface of the first substrate. The integrated circuit alsoincludes a second substrate having a first and second opposing surface.The second substrate is coupled to the base substrate such that thesecond surface of the second substrate is above the first surface of thebase substrate and the first surface of the second substrate is abovethe second surface of the second substrate. The integrated circuit alsoincludes an electronic component disposed on the first surface of thefirst substrate and a magnetic field sensing element disposed on thefirst surface of the second substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes a first magnetic field sensing elementhaving a first sensitivity to a magnetic field and a second magneticfield sensing element having a second different sensitivity to themagnetic field. The integrated circuit also includes a circuit coupledto the first and second magnetic field sensing elements. The circuit isoperable to provide the integrated circuit with a first sensitivityrange and a second different sensitivity range in response to themagnetic field.

In accordance with another aspect of the present invention, anintegrated circuit includes a first substrate and a circuit elementdisposed on a surface of the first substrate. The integrated circuitfurther includes a second substrate coupled to the first substrate and aHall effect element disposed on a surface of the second substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes first substrate and a circuit elementdisposed on a surface of the first substrate. A Hall effect element isdisposed on a surface of the first substrate. The integrated circuitalso includes a second substrate coupled to the first substrate and amagnetoresistance element disposed on a surface of the second substrate.

In accordance with another aspect of the present invention, anintegrated circuit includes a substrate, a first magnetic field sensingelement disposed on a surface of the substrate, and a second differenttype of magnetic field sensing element disposed on a surface of thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the invention, as well as the invention itselfmay be more fully understood from the following detailed description ofthe drawings, in which:

FIG. 1 is a pictorial showing an integrated circuit having first andsecond substrates, wherein the second substrate is a flip-chip;

FIG. 1A is a cross-sectional view of the integrated circuit of FIG. 1;

FIG. 2 is a pictorial showing another integrated circuit having firstand second substrates;

FIG. 2A is a cross-sectional view of the integrated circuit: of FIG. 1;

FIG. 3 is a pictorial showing another integrated circuit having firstand second substrates;

FIG. 3A is a cross-sectional view of the integrated circuit of FIG. 3;

FIG. 4 is a pictorial showing an integrated circuit having first andsecond substrates and a base substrate;

FIG. 4A is a cross-sectional view of the integrated circuit of FIG. 4;

FIG. 5 is a pictorial showing another integrated circuit having firstand second substrates and a base substrate;

FIG. 5A is a cross-sectional view of the integrated circuit of FIG. 5;

FIG. 6 is an exploded view showing an exemplary integrated currentsensor having first and second substrates and having an integratedcurrent-carrying conductor;

FIG. 7 is a pictorial showing another exemplary integrated currentsensor having first and second substrates and having an integratedcurrent-carrying conductor formed by coupling lead frame leads;

FIG. 7A is a cross-sectional view of the integrated circuit of FIG. 7;

FIG. 8 is a pictorial showing another exemplary integrated currentsensor having first and second substrates, three magnetic field sensors,and having an integrated current-carrying conductor formed by couplinglead frame leads; and

FIG. 8A is a cross-sectional view of the integrated circuit of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Before describing the present invention, some introductory concepts andterminology are explained. As used herein, the term “magnetic fieldsensing element” is used to describe an electronic component that isresponsive to and can be used to measure magnetic fields. The magneticfield sensing element can be of a type including, but not limited to, aHall effect element and a magnetoresistance element. The Hall effectelement can be a horizontal type or a vertical type. Themagnetoresistance element can be of a type including, but not limitedto, a giant magnetoresistance (GMR) element, an anisotropicmagnetoresistance (AMR) element, and a tunneling magnetoresistance (TMR)element.

As used herein, the term “magnetic field sensor” is used to describe anelectronic circuit, which includes a magnetic field sensing element, andwhich is responsive to and can be used to measure a magnetic field. Asused herein, the term “current sensor” is used to describe an electroniccircuit, which includes a magnetic field sensing element, and which isresponsive to and can be used to measure a current in a conductor.

It will be understood herein that a current in a conductor generates amagnetic field circularly disposed about the direction of current.Therefore, the magnetic field sensing element as used in a currentsensor can be used to measure the current flowing in a conductor.However, a magnetic field sensing element as used in a magnetic fieldsensor can be used to measure other magnetic fields, for example amagnetic field associated with the earth.

Referring to FIGS. 1 and 1A, in which like elements are shown havinglike reference designations, an exemplary integrated circuit 10 includesa lead frame 12, here shown as only a portion of a lead frame. It willbe understood that a lead frame can have a base plate and associatedleads. The leads are not shown in FIGS. 1 and 1A.

The integrated circuit 10 also includes a first substrate 14 havingfirst and second opposing surfaces 14 a, 14 b, respectively. The firstsubstrate 14 is coupled to the lead frame 12 such that the secondsurface 14 b of the first substrate 14 is above the lead frame 12 andthe first surface 14 a of the first substrate 14 is above the secondsurface 14 b of the first substrate 14.

The integrated circuit 10 also includes a second substrate 26 havingfirst and second opposing surfaces 26 a, 26 b, respectively. The firstsubstrate 14 and the second substrate 26 are coupled such that the firstsurface 26 a of the second substrate 26 is above the first surface 14 aof the first substrate 14 and the second surface 26 b of the secondsubstrate 26 is above the first surface 26 a of the second substrate 26.

The first and second substrates 14, 26, respectively, can be comprisedof a variety of materials including, but not limited to, Si, GaAs, InP,InSb, InGaAs, InGaAsP, SiGe, ceramic, or glass. The first and secondsubstrates 14, 26, respectively, can be comprised of the same materialor of different materials. In one particular embodiment, the firstsubstrate 14 is comprised of Silicon (Si) and the second substrate 26 iscomprised of Gallium Arsenide (GaAs).

The first surface 26 a of the second substrate 26 can be coupled to thefirst surface 14 a of the first substrate 14 with a selected one of asolder ball, a gold bump, a eutectic or high lead solder bump, a no-leadsolder bump, a gold stud bump, a polymeric conductive bump, ananisotropic conductive paste, or a conductive film. Four such couplings34 a-34 d are shown. However, it will be appreciated that the integratedcircuit 10 can have more than four or fewer than four such couplings.

The integrated circuit 10 also includes at least one electroniccomponent 18 disposed on the first surface 14 a of the first substrate14. The electronic component 18 can include, but is not limited to, apassive electronic component, for example, a resistor, capacitor, orinductor, and an active electronic component, for example, a transistor,an amplifier, or another integrated circuit.

The integrated circuit 10 also includes a first magnetic field sensingelement 30 disposed on the first surface 26 a of the second substrate26. It will be recognized that this arrangement provides a so-called“flip-chip” arrangement of the second substrate 26 relative to the firstsubstrate 14.

In some embodiments, the integrated circuit 10 further includes a secondmagnetic field sensing element 20 disposed on the first surface 14 a ofthe first substrate 14. The first and second magnetic field sensingelements 30, 20, respectively, can be selected ones of a Hall effectelement and a magnetoresistance element as described above. In someembodiments, the first and second magnetic field sensing elements 30,20, respectively, are the same type of magnetic field sensing element,and in other embodiments, the first and second magnetic field sensingelements 30, 20, respectively, are different types of magnetic fieldsensing elements.

In one particular embodiment, the first magnetic field sensing element30 is a Hall effect element and the second magnetic field sensingelement 20 is a magnetoresistance element, for example, a giantmagnetoresistance (GMR) element. In another particular embodiment, thefirst and second magnetic field sensing elements 30, 20, respectively,are both Hall effect elements, the first substrate is comprised ofSilicon and the second substrate 26 is comprised of GaAs. In someembodiments, the second magnetic field sensing element 20 is notpresent.

In some embodiments, the integrated circuit 10 can also include one ormore of a first or a second flux concentrator 32, 22, respectively eachdisposed proximate to an associated one of the first and second magneticfield sensing elements 30, 20, respectively. It will be understood thatsome materials, for example, ferrite, Permalloy, or other soft magneticmaterials, tend to concentrate flux, and their proximity can result inan increased magnetic field. Therefore, the flux concentrators 32, 22can provide an increased magnetic field proximate to the first andsecond magnetic field sensing elements 30, 20, respectively, resultingin an increased sensitivity of the first and second magnetic fieldsensing elements 30, 20 to a magnetic field, for example, a magneticfield resulting from a current in a conductor.

In some embodiments, the integrated circuit 10 also includes one or moreof a first resistor 28 formed on the second substrate 26 or a secondresistor 24 formed on the first substrate 14. The first and secondresistors 28, 24, respectively, can be used by the integrated circuit 10to measure resistivity changes in the first and second substrates 14,26, respectively, for example, over time or over temperature. One ofordinary skill in the art will understand how to construct circuits inconjunction with one or more of the resistors 24, 28, to accomplish thisend. In some arrangements, one of the first and second resistors 28, 24is not present, and the remaining one of the first and second resistors28, 24 is used to detect a resistivity change in one of the first andsecond substrates 14, 26, respectively.

The integrated circuit can also include a plurality of bonding pads, ofwhich bonding pads 16 a-16 c are representative. Bond wires 40 a-40 ccan couple the first and/or second substrates 14, 26, respectively, toleads (not shown) of the lead frame 12.

With an arrangement as shown, it will be recognized that packagingmaterials (not shown), e.g., plastic, that can be used to encase thefirst and second substrates 14, 26, respectively, would tend to resultin stresses and strains upon the second substrate 26. The resultingstresses and strains would tend to affect the sensitivity and linearityof the magnetic field sensing element 30, which is coupled to the secondsubstrate 26. The flip-chip arrangement tends to keep the magnetic fieldsensing element 30 from direct contact with the packaging material,therefore reducing the stresses and strains. To further reduce thestresses and strains, in some embodiments, the integrated circuit 10 caninclude an underfill material 42 disposed between the first surface 14 aof the first substrate 14 and the first surface 26 a of the secondsubstrate 26. The underfill material tends to keep the packagingmaterial, e.g., plastic, from contact with the magnetic field sensingelement 30, resulting in a further reduction of stresses and strainsupon the magnetic field sensing element 30 and upon the second substrate26.

The underfill material 42 can be comprised of a, for example Staychip™NUF-31071 E underfill material (Cookson Electronics Equipment, NewJersey).

It should be appreciated that various insulating layers (not shown) canbe used to electrically isolate portions of the integrated circuit 10from other portions of the integrated circuit 10. For example, aninsulating layer (not shown) can be disposed between the first surface14 a of the first substrate 14 and the flux concentrator 22. Also, aninsulating layer (not shown) can be disposed between the second surface26 b of the second substrate 26 and the flux concentrator 32.

In some embodiments, the flux concentrator 32 is instead disposedproximate to the first surface 26 a of the second substrate 26. In otherembodiments flux concentrators may be disposed on both the first andsecond surfaces 26 a, 26 b, respectively, of the second substrate 26.

For embodiments having the second magnetic field sensing element 20, insome arrangements, the second magnetic field sensing element 20 can havea different sensitivity to magnetic fields (i.e., currents) than thefirst magnetic field sensing element 30. Therefore, with thesearrangements, the integrated circuit 10 can have more than one “range,”or an extended range. With these arrangements, the integrated circuit 10can operate over a greater span of sensed currents, i.e., magnetic fieldstrengths.

In particular, for embodiments in which the second substrate 26 iscomprised of GaAs and the first substrate is comprised of Silicon andboth magnetic field sensing elements 30, 20 are Hall effect elements,the sensitivity of the magnetic field sensing element 30 is higher thanthe sensitivity of the second magnetic field sensing element 20.Therefore, an extended range of operation can be obtained while usingonly Hall effect elements.

Furthermore, for embodiments in which the second substrate 26 iscomprised of GaAs and the magnetic field sensing element 30 is a Halleffect element, and in which the first substrate 14 is comprised ofSilicon and the second magnetic field sensing element 20 is not present,a higher sensitivity can be achieved than for an arrangement having onlya Silicon based Hall effect element. With this arrangement, known costadvantages of having the circuitry 18 disposed on the silicon substrate14 can be achieved.

While the first substrate 14 is shown to be conventionally mounted tothe lead frame 12, i.e., with the first surface 14 a of the firstsubstrate 14 facing away from the lead frame 12, in other arrangements,the first substrate 14 can be flipped relative to the substrate 12. Inthese arrangements, the first surface 14 a of the first substrate 14 isproximate to the lead frame 12 and coupled to the lead frame with aselected one of a solder ball, a gold bump, a eutectic or high leadsolder bump, a no-lead solder bump, a gold stud bump, a polymericconductive bump, an anisotropic conductive paste, or a conductive film.In these arrangements, the first surface 26 a of the second substrate 26remains coupled as shown to the first surface 14 a of the firstsubstrate 14, wherein the first surfaces 14 a, 26 a of the substrates14, 26, respectively are proximate to each other.

Referring now to FIGS. 2 and 2A, in which like elements are shown havinglike reference designators, an integrated circuit 50 includes aspectssimilar to the integrated circuit 10 of FIGS. 1 and 1A, but without theflip-chip arrangement of FIGS. 1 and 1A.

The integrated circuit 50 includes a lead frame 52. The integratedcircuit 50 also includes a first substrate 54 having first and secondopposing surfaces 54 a, 54 b, respectively. The first substrate 54 iscoupled to the lead frame 52 such that the second surface 54 b of thefirst substrate 54 is above the lead frame 52 and the first surface 54 aof the first substrate 54 is above the second surface 54 b of the firstsubstrate 54.

The integrated circuit 50 also includes a second substrate 66 havingfirst and second opposing surfaces 66 a, 66 b, respectively. The firstsubstrate 54 and the second substrate 66 are coupled such that thesecond surface 66 b of the second substrate 66 is above the firstsurface 54 a of the first substrate 54 and the first surface 66 a of thesecond substrate 66 is above the second surface 66 b of the secondsubstrate 66.

The first and second substrates 54, 66, respectively can be comprised ofa variety of materials including, but not limited to, Si, GaAs, InP,InSb, InGaAs, InGaAsP, SiGe, ceramic, or glass. The first and secondsubstrates 54, 66, respectively, can be comprised of the same materialor of different materials. In one particular embodiment, the firstsubstrate 54 is comprised of Silicon (Si) and the second substrate 66 iscomprised of Gallium Arsenide (GaAs).

The first surface 66 a of the second substrate 66 can be coupled to thefirst surface 54 a of the first substrate 54 with wire bonds 74 a-74 d.Four such couplings 74 a-74 d are shown. However, it will be appreciatedthat the integrated circuit 50 can have more than four or fewer thanfour such couplings.

The integrated circuit 50 also includes at least one electroniccomponent 56 disposed on the first surface 54 a of the first substrate54. The electronic component 56 can include, but is not limited to, apassive electronic component, for example, a resistor, capacitor, orinductor, and an active electronic component, for example, a transistor,an amplifier, or another integrated circuit.

The integrated circuit 50 also includes a first magnetic field sensingelement 70 disposed on the first surface 66 a of the second substrate66.

In some embodiments, the integrated circuit 50 further includes a secondmagnetic field sensing element 58 disposed on the first surface 54 a ofthe first substrate 54. The first and second magnetic field sensingelements 70, 58, respectively, can be selected ones of a Hall effectelement and a magnetoresistance element as described above. In someembodiments, the first and second magnetic field sensing elements 70,58, respectively, are the same type of magnetic field sensing element,and in other embodiments, the first and second magnetic field sensingelements 70, 58, respectively, are different types of magnetic fieldsensing elements.

In one particular embodiment, the first magnetic field sensing element70 is a Hall effect element and the second magnetic field sensingelement 58 is a magnetoresistance element, for example, a giantmagnetoresistance (GMR) element. In another particular embodiment, thefirst and second magnetic field sensing elements 70, 58, respectively,are both Hall effect elements, the first substrate 54 is comprised ofSilicon and the second substrate 66 is comprised of GaAs. In someembodiments, the second magnetic field sensing element 58 is notpresent.

In some embodiments, the integrated circuit 50 can also include one ormore of a first or a second flux concentrator 71, 59, respectively, eachdisposed proximate to an associated one of the first and second magneticfield sensing elements 70, 58, respectively. The flux concentrators 71,59 can provide an increased magnetic field proximate to the first andsecond magnetic field sensing elements 70, 58 and a correspondingincreased sensitivity of the first and second magnetic field sensingelements 70, 58 to a magnetic field, for example, a magnetic fieldresulting from a current in a conductor.

In some embodiments, the integrated circuit 50 also includes one or moreof a first resistor 68 formed on the second substrate 66 or a secondresistor 60 formed on the first substrate 54. The first and secondresistors 68, 60, respectively, can be used by the integrated circuit 50to measure resistivity changes in the first and second substrates 54,66, respectively, for example, over time or over temperature. Asdescribed above in conjunction with FIGS. 1 and 1A, one of ordinaryskill in the art will understand how to construct circuits inconjunction with one or more of the resistors 68, 60, to accomplish thisend. In some arrangements, one of the first and second resistors 68, 60is not present, and the remaining one of the first and second resistors68, 60 is used to detect a resistivity change in one of the first andsecond substrates 54, 66, respectively.

The integrated circuit 50 can also include a plurality of bonding pads,of which bonding pads 76 a-76 c are representative. Bond wires 78 a-78 ccan couple the first and/or second substrates 54, 66, respectively, toleads (not shown) of the lead frame 52.

It should be appreciated that various insulating layers can be used toelectrically isolate portions of the integrated circuit 50 from otherportions of the integrated circuit 50. For example, an insulating layer64 can be disposed between the first surface 14 a of the first substrate14 and the second surface 66 b of the second substrate 66.

For embodiments having the second magnetic field sensing element 58, insome arrangements, the second magnetic field sensing element 58 can havea different sensitivity to magnetic fields (i.e., currents) than thefirst magnetic field sensing element 70. Therefore, with thesearrangements, the integrated circuit 10 can have more than one “range,”or an extended range. With these arrangements, the integrated circuit 50can operate over a greater span of sensed currents, i.e., magnetic fieldstrengths.

Exemplary combinations of types of magnetic field sensing elements andsubstrate materials are further described above in conjunction withFIGS. 1 and 1A. At least the same combinations apply to the integratedcircuit 50.

Referring now to FIGS. 3 and 3A, in which like elements are shown havinglike reference designators, an integrated circuit 100 includes aspectssimilar to the integrated circuit 10 of FIGS. 1 and 1A.

The integrated circuit 100 includes a lead frame 102. The integratedcircuit 100 also includes a first substrate 114 having first and secondopposing surfaces 114 a, 114 b, respectively. The integrated circuit 100also includes a second substrate 104 having first and second opposingsurfaces 104 a, 104 b, respectively.

The first substrate 114 is coupled to the lead frame 102 such that thesecond surface 114 b of the first substrate 114 is above the lead frame102 and the first surface 114 a of the first substrate 114 is above thesecond surface 114 b of the first substrate 114. The second substrate104 is coupled to the lead frame 102 such that the second surface 104 bof the second substrate 104 is above the lead frame 102 and the firstsurface 104 a of the second substrate 104 is above the second surface104 b of the second substrate 104.

The first and second substrates 114, 104, respectively can be comprisedof a variety of materials including, but not limited to, Si, GaAs, InP,InSb, InGaAs, InGaAsP, SiGe, ceramic, or glass. The first and secondsubstrates 114, 104, respectively, can be comprised of the same materialor of different materials. In one particular embodiment, the firstsubstrate 114 is comprised of Silicon (Si) and the second substrate 104is comprised of Gallium Arsenide (GaAs).

The first surface 104 a of the second substrate 104 can be coupled tothe first surface 114 a of the first substrate 114 with wire bonds 112a-112 d. Four such couplings 112 a-112 d are shown. However, it will beappreciated that the integrated circuit 100 can have more than four orfewer than four such couplings.

The integrated circuit 100 also includes at least one electroniccomponent 118 disposed on the first surface 114 a of the first substrate114. The electronic component 118 can include, but is not limited to, apassive electronic component, for example, a resistor, capacitor, orinductor, and an active electronic component, for example, a transistor,an amplifier, or another integrated circuit.

The integrated circuit 100 also includes a first magnetic field sensingelement 106 disposed on the first surface 104 a of the second substrate104.

In some embodiments, the integrated circuit 100 further includes asecond magnetic field sensing element 116 disposed on the first surface114 a of the first substrate 114. The first and second magnetic fieldsensing elements 106, 116, respectively, can be selected ones of a Halleffect element and a magnetoresistance element as described above. Insome embodiments, the first and second magnetic field sensing elements106, 116, respectively, are the same type of magnetic field sensingelement, and in other embodiments, the first and second magnetic fieldsensing elements 106, 116, respectively, are different types of magneticfield sensing elements.

In one particular embodiment, the first magnetic field sensing element106 is a Hall effect element and the second magnetic field sensingelement 116 is a magnetoresistance element, for example, a giantmagnetoresistance (GMR) element. In another particular embodiment, thefirst and second magnetic field sensing elements 106, 116, respectively,are both Hall effect elements, the first substrate 114 is comprised ofSilicon and the second substrate 104 is comprised of GaAs. In someembodiments, the second magnetic field sensing element 116 is notpresent.

In some embodiments, the integrated circuit 100 can also include one ormore of a first or a second flux concentrator (not shown) each disposedproximate to an associated one of the first and second magnetic fieldsensing elements 106, 116, respectively. The flux concentrators (notshown) can provide an increased magnetic field proximate to the firstand second magnetic field sensing elements 106, 116 and a correspondingincreased sensitivity of the first and second magnetic field sensingelements 106, 116 to a magnetic field, for example, a magnetic fieldresulting from a current in a conductor.

In some embodiments, the integrated circuit 100 also includes one ormore of a first resistor 108 formed on the second substrate 104 or asecond resistor 120 formed on the first substrate 114. The first andsecond resistors 108, 120, respectively, can be used by the integratedcircuit 100 to measure resistivity changes in the first and secondsubstrates 114, 104, respectively, for example, over time or overtemperature. As described above in conjunction with FIG. 1, one ofordinary skill in the art will understand how to construct circuits inconjunction with one or more of the resistors 108, 120, to accomplishthis end. In some arrangements, one of the first and second resistors108, 120 is not present, and the remaining one of the first and secondresistors 108, 120 is used to detect a resistivity change in one of thefirst and second substrates 114, 104, respectively.

The integrated circuit 100 can also include a plurality of bonding pads,of which bonding pads 124 a-124 c are representative. Bond wires 126a-126 c can couple the first substrates 114 to leads (not shown) of thelead frame 102.

It should be appreciated that various insulating layers can be used toelectrically isolate portions of the integrated circuit 100 from otherportions of the integrated circuit 100. For example, insulating layers(not shown) can be disposed between the second surface 114 b of thefirst substrate 114 and the lead frame 102 and also between the secondsurface 104 b of the first substrate 104 and the lead frame 102.

For embodiments having the second magnetic field sensing element 116, insome arrangements, the second magnetic field sensing element 116 canhave a different sensitivity to magnetic fields (i.e., currents) thanthe first magnetic field sensing element 106. Therefore, with thesearrangements, the integrated circuit 100 can have more than one “range,”or an extended range. With these arrangements, the integrated circuit100 can operate over a greater span of sensed currents, i.e., magneticfield strengths.

Exemplary combinations of types of magnetic field sensing elements andsubstrate materials are further described above in conjunction withFIGS. 1 and 1A. At least the same combinations apply to the integratedcircuit 100.

Referring now to FIGS. 4 and 4A, in which like elements are shown havinglike reference designators, an integrated circuit 150 includes aspectssimilar to the integrated circuit 10 of FIGS. 1 and 1A, including aflip-chip arrangement as shown in FIGS. 1 and 1A.

The integrated circuit 150 includes a lead frame 152 and a basesubstrate 154 having first and second opposing surfaces 154 a, 154 b,respectively. The base substrate can be comprised of a variety ofmaterials, for example, ceramic, glass, polymer, i.e. FR-4, or asemiconductor. The integrated circuit 150 also includes a firstsubstrate 156 having first and second opposing surfaces 156 a, 156 b,respectively, and a second substrate 166 having first and secondopposing surfaces 166 a, 166 b, respectively.

The base substrate 154 is coupled to the lead frame 152 such that thesecond surface 154 b of the base substrate 154 is above the lead frame152 and the first surface 154 a of the base substrate 154 is above thesecond surface 154 b of the base substrate 154. The first substrate 156is coupled to the base substrate 154 such that the first surface 156 aof the first substrate 156 is above the first surface 154 a of the basesubstrate 154 and the second surface 156 b of the first substrate 156 isabove the first surface 156 a of the first substrate 156. The secondsubstrate 166 is coupled to the base substrate 154 such that the firstsurface 166 a of the second substrate 166 is above the first surface 154a of the base substrate 154 and the second surface 166 b of the secondsubstrate 166 is above the first surface 166 a of the second substrate166.

The first and second substrates 156, 166, respectively can be comprisedof a variety of materials including, but not limited to, Si, GaAs, InP,InSb, InGaAs, InGaAsP, SiGe, ceramic, or glass. The first and secondsubstrates 156, 166, respectively, can be comprised of the same materialor of different materials. In one particular embodiment, the firstsubstrate 156 is comprised of Silicon (Si) and the second substrate 166is comprised of Gallium Arsenide (GaAs).

The first surface 166 a of the second substrate 166 can be coupled tothe first surface 154 a of the base substrate 154 with a conductiveelement, for example, of a solder ball, a gold bump, a eutectic or highlead solder bump, a no-lead solder bump, a gold stud bump, a polymericconductive bump, an anisotropic conductive paste, or a conductive film.Four such couplings 172 a-172 c are shown. However, it will beappreciated that the integrated circuit 150 can have more than four orfewer than four such couplings.

The first surface 156 a of the second substrate 156 can also be coupledto the first surface 154 a of the base substrate 154 with a selected oneof a solder ball, a gold bump, a eutectic or high lead solder bump, ano-lead solder bump, a gold stud bump, a polymeric conductive bump, ananisotropic conductive paste, or a conductive film. Four such couplings164 a-164 c are shown. However, it will be appreciated that theintegrated circuit 150 can have more than four or fewer than four suchcouplings.

With this arrangement, the base substrate 154 can have conductive tracesor the like (not shown) to couple the first substrate 156 to the secondsubstrate 166, and to the pads 174 a-c.

The integrated circuit 150 also includes at least one electroniccomponent 158 disposed on the first surface 156 a of the first substrate156. The electronic component 158 can include, but is not limited to, apassive electronic component, for example, a resistor, capacitor, orinductor, and an active electronic component, for example, a transistor,an amplifier, or another integrated circuit.

The integrated circuit 150 also includes a first magnetic field sensingelement 168 disposed on the first surface 166 a of the second substrate166.

In some embodiments, the integrated circuit 150 further includes asecond magnetic field sensing element 160 disposed on the first surface156 a of the first substrate 156. The first and second magnetic field,sensing elements 168, 160, respectively, can be selected ones of a Halleffect element and a magnetoresistance element as described above. Insome embodiments, the first and second magnetic field sensing elements168, 160, respectively, are the same type of magnetic field sensingelement, and in other embodiments, the first and second magnetic fieldsensing elements 168, 160, respectively, are different types of magneticfield sensing elements.

In one particular embodiment, the first magnetic field sensing element168 is a Hall effect element and the second magnetic field sensingelement 160 is a magnetoresistance element, for example, a giantmagnetoresistance (GMR) element. In another particular embodiment, thefirst and second magnetic field sensing elements 168, 160, respectively,are both Hall effect elements, the first substrate 156 is comprised ofSilicon and the second substrate 166 is comprised of GaAs. In someembodiments, the second magnetic field sensing element 160 is notpresent.

In some embodiments, the integrated circuit 150 can also include one ormore of a first or a second flux concentrator (not shown) each disposedproximate to an associated one of the first and second magnetic fieldsensing elements 168, 160, respectively. The flux concentrators (notshown) can provide an increased magnetic field proximate to the firstand second magnetic field sensing elements 168, 160 and a correspondingincreased sensitivity of the first and second magnetic field sensingelements 168, 160 to a magnetic field, for example, a magnetic fieldresulting from a current in a conductor.

In some embodiments, the integrated circuit 150 also includes one ormore of a first resistor 170 formed on the second substrate 166 or asecond resistor 162 formed on the first substrate 156. The first andsecond resistors 170, 162, respectively, can be used by the integratedcircuit 150 to measure resistivity changes in the first and secondsubstrates 156, 166, respectively, for example, over time or overtemperature. As described above in conjunction with FIGS. 1 and 1A, oneof ordinary skill in the art will understand how to construct circuitsin conjunction with one or more of the resistors 170, 162, to accomplishthis end. In some arrangements, one of the first and second resistors170, 162 is not present, and the remaining one of the first and secondresistors 170, 162 is used to detect a resistivity change in one of thefirst and second substrates 156, 166, respectively.

The integrated circuit 150 can also include a plurality of bonding pads,of which bonding pads 174 a-174 c are representative. Bond wires 176a-176 c can couple the first and/or second substrates 156, 166,respectively, to leads (not shown) of the lead frame 152.

It should be appreciated that various insulating layers (not shown) canbe used to electrically isolate portions of the integrated circuit 150from other portions of the integrated circuit 150.

For embodiments having the second magnetic field sensing element 160, insome arrangements, the second magnetic field sensing element 160 canhave a different sensitivity to magnetic fields (i.e., currents) thanthe first magnetic field sensing element 168. Therefore, with thesearrangements, the integrated circuit 150 can have more than one “range,”or an extended range. With these arrangements, the integrated circuit150 can operate over a greater span of sensed currents, i.e., magneticfield strengths.

Exemplary combinations of types of magnetic field sensing elements andsubstrate materials are further described above in conjunction withFIGS. 1 and 1A. At least the same combinations apply to the integratedcircuit 150.

While only the first and second substrates 156, 166, respectively, areshown to be coupled to the base substrate 154, it will be appreciatedthat in other arrangements there can be more than two or fewer than twosubstrates coupled to the base substrate 154.

Referring now to FIGS. 5 and 5A, in which like elements are shown havinglike reference designators, an integrated circuit 200 includes aspectssimilar to the integrated circuit 10 of FIGS. 1 and 1A.

The integrated circuit 200 includes a lead frame 202 and a basesubstrate 204 having first and second opposing surfaces 204 a, 204 b,respectively. The base substrate can be comprised of a variety ofmaterials, for example, ceramic, glass, polymer, i.e. FR-4, or asemiconductor. The integrated circuit 200 also includes a firstsubstrate 216 having first and second opposing surfaces 216 a, 216 b,respectively, and a second substrate 206 having first and secondopposing surfaces 206 a, 206 b, respectively.

The base substrate 204 is coupled to the lead frame 202 such that thesecond surface 204 b of the base substrate 204 is above the lead frame202 and the first surface 204 a of the base substrate 204 is above thesecond surface 204 b of the base substrate 204. The first substrate 216is coupled to the base substrate 204 such that the second surface 216 bof the first substrate 216 is above the first surface 204 a of the basesubstrate 204 and the first surface 216 a of the first substrate 216 isabove the second surface 216 b of the first substrate 216. The secondsubstrate 206 is coupled to the base substrate 204 such that the secondsurface 206 b of the second substrate 206 is above the first surface 204a of the base substrate 204 and the first surface 206 a of the secondsubstrate 206 is above the second surface 206 b of the second substrate206.

The first and second substrates 216, 206, respectively can be comprisedof a variety of materials including, but not limited to, Si, GaAs, InP,InSb, InGaAs, InGaAsP, SiGe, ceramic, or glass. The first and secondsubstrates 216, 206, respectively, can be comprised of the same materialor of different materials. In one particular embodiment, the firstsubstrate 216 is comprised of Silicon (Si) and the second substrate 206is comprised of Gallium Arsenide (GaAs).

The first surface 206 a of the second substrate 206 can be coupled tothe first surface 216 a of the first substrate 216 with wire bonds 214a-214 d. Four such couplings 214 a-214 d are shown. However, it will beappreciated that the integrated circuit 200 can have more than four orfewer than four such couplings.

The integrated circuit 200 also includes at least one electroniccomponent 220 disposed on the first surface 216 a of the first substrate216. The electronic component 220 can include, but is not limited to, apassive electronic component, for example, a resistor, capacitor, orinductor, and an active electronic component, for example, a transistor,an amplifier, or another integrated circuit.

The integrated circuit 200 also includes a first magnetic field sensingelement 208 disposed on the first surface 206 a of the second substrate206.

In some embodiments, the integrated circuit 200 further includes asecond magnetic field sensing element 218 disposed on the first surface216 a of the first substrate 216. The first and second magnetic fieldsensing elements 208, 218, respectively, can be selected ones of a Halleffect element and a magnetoresistance element as described above. Insome embodiments, the first and second magnetic field sensing elements208, 218, respectively, are the same type of magnetic field sensingelement, and in other embodiments, the first and second magnetic fieldsensing elements 208, 218, respectively, are different types of magneticfield sensing elements.

In one particular embodiment, the first magnetic field sensing element208 is a Hall effect element and the second magnetic field sensingelement 218 is a magnetoresistance element, for example, a giantmagnetoresistance (GMR) element. In another particular embodiment, thefirst and second magnetic field sensing elements 208, 218, respectively,are both Hall effect elements, the first substrate 216 is comprised ofSilicon and the second substrate 206 is comprised of GaAs. In someembodiments, the second magnetic field sensing element 218 is notpresent.

In some embodiments, the integrated circuit 200 can also include one ormore of a first or a second flux concentrator (not shown) each disposedproximate to an associated one of the first and second magnetic fieldsensing elements 208, 218, respectively. The flux concentrators (notshown) can provide an increased magnetic field proximate to the firstand second magnetic field sensing elements 208, 218 and a correspondingincreased sensitivity of the first and second magnetic field sensingelements 208, 218 to a magnetic field, for example, a magnetic fieldresulting from a current in a conductor.

In some embodiments, the integrated circuit 200 also includes one ormore of a first resistor 210 formed on the second substrate 206 or asecond resistor 222 formed on the first substrate 216. The first andsecond resistors 210, 222, respectively, can be used by the integratedcircuit 200 to measure resistivity changes in the first and secondsubstrates 216, 206, respectively, for example, over time or overtemperature. As described above in conjunction with FIGS. 1 and 1A, oneof ordinary skill in the art will understand how to construct circuitsin conjunction with one or more of the resistors 210, 222, to accomplishthis end. In some arrangements, one of the first and second resistors210, 222 is not present, and the remaining one of the first and secondresistors 210, 222 is used to detect a resistivity change in one of thefirst and second substrates 216, 206, respectively.

The integrated circuit 200 can also include a plurality of bonding pads,of which bonding pads 232 a-232 c are representative. Bond wires 234a-234 c can couple the first and/or second substrates 216, 206,respectively, to leads (not shown) of the lead frame 202.

It should be appreciated that various insulating layers (not shown) canbe used to electrically isolate portions of the integrated circuit 200from other portions of the integrated circuit 200.

For embodiments having the second magnetic field sensing element 218, insome arrangements, the second magnetic field sensing element 218 canhave a different sensitivity to magnetic fields (i.e., currents) thanthe first magnetic field sensing element 208. Therefore, with thesearrangements, the integrated circuit 200 can have more than one “range,”or an extended range. With these arrangements, the integrated circuit200 can operate over a greater span of sensed currents, i.e., magneticfield strengths.

Exemplary combinations of types of magnetic field sensing elements andsubstrate materials are farther described above in conjunction withFIGS. 1 and 1A. At least the same combinations apply to the integratedcircuit 200.

Referring now to FIG. 6, an integrated circuit 250, shown in an explodedview, includes a first substrate 252, a second substrate 254, and a leadframe 257. The first substrate 252, second substrate 254, and the leadframe 257 can be the same as or similar to similar elements of any ofthe integrated circuit 10, 50, 100, 150, and 200 of FIGS. 1-1A, 2-2A,3-3A, 4-4A, and 5-5A, respectively.

The second substrate 254 includes a magnetic field sensing element 256,which can be a selected one of a Hall effect element or amagnetoresistance element. It will be appreciated that a position of themagnetic field sensing element 256 can be selected in accordance with anaxis of sensitivity of the magnetic field sensing element 256 relativeto a magnetic field that is being sensed. The integrated circuit 250also includes a current-carrying conductor 258 and a magnetic core 260(also referred to herein as a flux concentrator). The magnetic core 260is substantially C-shaped and has a central region 260 a and a pair ofsubstantially parallel legs 260 b, 260 c extending from the centralregion 260 a. When assembled, the flux concentrator 260 is shaped sothat the leg 260 b is disposed under the lead frame 257 and the otherleg 260 c is disposed above the second substrate 254.

The lead frame 275 has leads 259 adapted for mounting to a printedcircuit board (not shown). The leads 259, can include, for example, apower, or Vcc, connection, a ground connection, and an output connectionadapted to carry an output signal proportional to the current throughthe conductor 258. The output signal may be a current or a voltage.

The first substrate 252 includes circuitry (not shown) for processingthe output signal of the Hall effect element 256

The conductor 258 can be comprised of various conductive materials, suchas copper, and is adapted for mounting to a printed circuit boardthrough which the measured current is provided to the conductor 258. Tothis end, bent leads or tabs 258 a, 258 b (258 b not shown) suitable forsoldering into circuit board vias are provided at end portions of theconductor 258. Mechanisms other than bent tabs 258 a, 258 b may be usedto mount the integrated circuit 250 to a circuit board, such as screwterminals and associated. In alternate embodiments, the same or othermounting mechanisms can be used to allow the integrated circuit 250 tobe mounted to other than a circuit board. For example, the integratedcircuit 250 can have wire couplings (not shown) that allow theintegrated circuit 250 to be coupled in series with a wire.

The conductor 258 (excluding the bent tabs 258 a, 258 b) can besubstantially planar as shown, without features extending in a z-axis266 which would tend to increase the height of the integrated circuit250 off of a printed circuit board. In use, the plane of the conductor258 is positioned close to the printed circuit board plane, therebyproviding a low profile integrated circuit.

The flux concentrator 260 tends to tailor the magnetic field across theHall effect element 256. The flux concentrator 260 may be comprised ofvarious materials including, but not limited to ferrite, steel, ironcompounds, Permalloy, or other soft magnetic materials. The material ofthe flux concentrator 260 is selected, based on factors such as maximummeasured current and the desired amount of magnetic shielding providedby the flux concentrator 260. Other factors include stability of therelative permeability over temperature and hysteresis (magneticremaneuce). For example, a low hysteresis ensures greater accuracy forsmall currents through the conductor 258. The material and size of theflux concentrator 260 are also selected in accordance with the desiredfull scale current through the conductor 258, wherein a magnetic corematerial with a higher saturation flux density (Bsat) allows the use ofa smaller core for a given current flowing through the conductor 258. Itwill be appreciated that use of the flux concentrator 260 significantlyreduces the susceptibility of the integrated circuit to stray magneticfields.

Referring now to FIGS. 7 and 7A, in which like elements are shown havinglike reference designations, an integrated circuit 300 includes a leadframe 302 having a plurality of leads 302 a-302 h, a first substrate306, and a second substrate 307.

The leads 302 a and 302 b are coupled to the leads 302 c and 302 d toform a current path, or current conductor with a narrow portion 304having a width w1. The first substrate 306 has a first surface 306 a anda second, opposing surface 306 b and the second substrate 307 has afirst surface 307 a and a second, opposing surface 307 b. The firstsubstrate 306 can have a magnetic field sensing element 308, which, insome embodiments, can be a Hall effect element 308, diffused into thefirst surface 306 a, or otherwise disposed on the first surface 306 a ofthe first substrate 306. Similarly, the second substrate 307 can have amagnetic field sensing element 309, which, in some embodiments, can be aHall effect element 309, diffused into the first surface 307 a, orotherwise disposed on the first surface 307 a of the second substrate307.

The first and second substrates 306, 307, respectively, are shown to becoupled together in a flip-chip arrangement similar to the integratedcircuit 10 of FIG. 1. As described above in conjunction with FIGS. 1 and1A, the first substrate 14 of FIGS. 1 and 1A can be mounted in aflip-chip arrangement to the substrate 12, which arrangement is shown inFIG. 7. However, in other embodiments, it should be recognized that anintegrated circuit similar to the integrated circuit 300 can be formedfrom any of the arrangements of FIGS. 2-2A, 3-3A, 4-4A, and 5-5A.

The substrate 306 is disposed above the lead frame 302 so that the firstsurface 306 a is proximate to the current conductor portion 304 and thesecond surface 306 b is distal from the current conductor portion 304and more specifically, so that the Hall effect element 308 is in closeproximity to the current conductor portion 304. Similarly, the magneticfield sensing element 309 of the second substrate 307 is in closeproximity to the current conductor portion 304. In the illustratedembodiment, the substrate 306 has an orientation that is upside down(i.e., the first surface 306 a is directed downward) relative to aconventional orientation with which a substrate is mounted in anintegrated circuit package.

The first substrate 306 has bonding pads 310 a-310 c on the firstsurface 306 a, to which bond wires 312 a-312 c are coupled. The bondwires are further coupled to the leads 302 e, 302 f, 302 h of the leadframe 302.

An insulator 314 separates and electrically isolates the substrate 306from the lead frame 302. The insulator 314 can be provided in a varietyof ways. For example, in one embodiment, a first portion of theinsulator 314 includes a four μm thick layer of a BCB resin materialdeposited directly on the first surface 306 a of the substrate 306. Asecond portion of the insulator 314 includes a layer of Staychip™NUF-31071 E underfill material (Cookson Electronics Equipment, NewJersey) deposited on the lead frame 302. Such an arrangement providesmore than one thousand volts of isolation between the substrate 306 andthe lead frame 302.

It will be understood that the current conductor portion 304 is but apart of the total path through which an electrical current flows. Forexample, a current having a direction depicted by arrows 316 flows intothe leads 302 c, 302 d, which are here shown to be electrically coupledin parallel, through the current conductor portion 304, and out of theleads 302 a, 302 b, which are also shown here to be electrically coupledin parallel.

With this arrangement, the Hall effect elements 308, 309 are disposed inclose proximity to the current conductor portion 304 and at apredetermined position relative to the current conductor portion 304,such that a magnetic field generated by an electrical current passingthough the current conductor portion 304, in a direction shown by arrows316, is in a direction substantially aligned with a maximum responseaxis of the Hall effect elements 308, 309. The Hall effect elements 308,309 generate respective voltage outputs proportional to the magneticfield and therefore proportional to the current flowing through thecurrent conductor portion 304. The illustrated Hall effect elements 308,309 have a maximum response axis substantially aligned with a z-axis324. Because the magnetic field generated in response to the current iscircular about the current conductor portion 304, the Hall effectelements 308, 309 are disposed just to the side (i.e., slightly offsetalong a y-axis 322) of the current conductor portion 304, as shown,where the magnetic field is pointed substantially along the z-axis 324.This position results in a greater voltage output from the Hall effectelements 308, 309 and therefore, improved sensitivity. However, avertical Hall effect element, or another type of magnetic field sensor,for example a magnetoresistance element, having a maximum response axisaligned in another direction, can be disposed at another positionrelative to the current conductor portion 304, for example, on top ofthe current conductor portion 304 (in a direction along z-axis 324).

In the embodiment of FIG. 7, the close proximity between the Hall effectelements 308, 309 and the current conductor 304 is achieved by providingthe Hall effect element 308 on the first surface 306 a of the firstsubstrate 306, and by providing the Hall effect element 309 on the firstsurface 307 a of the second substrate 307.

Referring now to FIGS. 8 and 8A, in which like elements are shown havinglike reference designations, another exemplary integrated circuit 350includes a lead frame 352 having a plurality of leads 352 a-352 h and acurrent conductor portion 354 provided as a combination of a firstcurrent conductor portion 354 a and a second current conductor portion354 b. The integrated circuit 350 also includes a substrate 356 having afirst surface 356 a and a second, opposing, surface 356 b. The substrate356 has a Hall effect element 358 diffused into the first surface 356 a,or otherwise disposed on or supported by the first surface 356 a. Thesubstrate 356 also has two magnetoresistance elements 360 a, 360 bdisposed on or otherwise supported by the first surface 356 a of thesubstrate 356. The substrate 356 is disposed on the lead frame 352 sothat the Hall effect element 358 and the magnetoresistance elements 360a, 360 b are in close proximity to the current conductor portion 354.

In the illustrated embodiment, the substrate 356 has an orientation thatis upside down (i.e., the first surface 356 a is directed downward) inrelation to the conventional orientation of a substrate mounted in anintegrated circuit package. The substrate 356 is a flip-chip havingsolder balls 362 a-362 e on the first surface 356 a of the substrate356. The solder balls 362 a-362 e couple directly to the leads 352 e-352h. An insulator (not shown) can separate and electrically isolate thesubstrate 356 from the lead frame 352.

In one particular embodiment, the second current conductor portion 354 bis deposited on the first surface 356 a of the substrate 356, whileavoiding, or being otherwise insulated from, the two magnetoresistanceelements 360 a, 360 b. The second current conductor portion 354 b can bedeposited by any conventional integrated circuit deposition technique,including, but not limited to, sputtering and electroplating, in otherembodiments, the second current conductor portion 354 b is a conductivestructure separate from, but proximate to, the first surface 356 a ofthe substrate 356.

With this arrangement, the Hall effect element 358 and themagnetoresistance elements 360 a, 360 b are disposed in close proximityto the current conductor portion 354 and at a predetermined positionrelative to the current conductor portion 354 such that a magnetic fieldgenerated by an electrical current passing though the current conductorportion 354 is in a direction substantially aligned with a maximumresponse axis of the Hall effect element 358 and with the maximumresponse axes of the magnetoresistance elements 360 a, 360 b. Here, theHall effect element 358 has a maximum response axis aligned with az-axis 363 and the two magnetoresistance elements have maximum responseaxes substantially aligned with an x-axis 364. Therefore, the Halleffect element 358 is disposed to a side (i.e., slightly offset along ay-axis 324) of the current conductor portion 354, as shown, where themagnetic field is pointed along the z-axis 328. The magnetoresistanceelements 360 a, 360 b, however, are disposed in a z-axis alignment withrespect to the current conductor portion 354.

In operation, the current 316 flows into the leads 352 c, 352 d, whichare coupled in parallel, through the current conductor portion 354, andout of the leads 352 a, 352 b, which are also coupled in parallel. Thecurrent 316 flowing though the current conductor portion 354 generates amagnetic field, which is sensed by the Hall effect element 358 and bythe two magnetoresistance elements 360 a, 360 b, providing a dual-levelcurrent sensor or an extended range current sensor in much the samefashion as described above for embodiments having two substrates.

In other embodiments, the magnetoresistance elements 360 a, 360 b can bereplaced with vertical Hall effect elements.

As described above, the Hall effect element 358 and themagnetoresistance elements 360 a, 360 b are in very close proximity tothe current conductor portion 354 and at a predetermined positionrelative to the current conductor portion 354 at which the magneticfield generated by the current is substantially aligned with the maximumresponse axis of the elements. This placement results in a greatervoltage output from the Hall effect element 358 and from themagnetoresistance elements 360 a, 360 b, and therefore, greatersensitivity.

With this arrangement, it will be appreciated that the current flowingthrough the current conductor portion 354 splits between the first andsecond current conductor portions 354 a, 354 b, respectively.

While the lead frame 352 is shown to have the bent leads 352 a-352 hsuitable for surface mounting to a circuit board, it will be appreciatedthat a lead frame having leads with other shapes can also be used,including but not limited to, through hole leads having a straightshape.

While only one Hall effect element 358 is shown on the first surface 356a of the substrate 356, it will be appreciated that more than one Halleffect element can be used. Furthermore, while two magnetoresistanceelements 360 a, 360 b are shown, it will be appreciated that more thantwo or fewer than two magnetoresistance elements can be used. Othercircuitry, for example an amplifier, can also be diffused on orotherwise coupled to or supported by the first and/or second surfaces356 a, 356 b of the substrate 356.

While five solder balls 320 a-320 e are shown, any number of solderballs can be provided, including dummy solder balls for stabilizing thesubstrate 356. Also, while solder balls 320 a-320 e are shown, otherconnection methods can also be used, including, but not limited to goldbumps, eutectic or high lead solder humps, no-lead solder bumps, goldstud bumps, polymeric conductive bumps, anisotropic conductive paste,conductive film, and wire bonds.

While the substrate is 356 is shown in a flip-chip arrangement, in otherembodiments, the substrate 356 can be conventionally mounted such thatthe first surface 356 a is above the second surface 356 b when theintegrated circuit 350 is normally mounted to an uppermost surface of acircuit board. With these arrangements, the first and second currentconductor portions 354 a, 354 b, respectively, are each above the firstsurface 356 a of the substrate 356.

The integrated circuits described above in conjunction with FIGS. 1, 1A,2, 2A, 3, 3A, 4, 5A, 5 and 5A are discussed as used in current sensors,wherein the various magnetic field sensing elements disposed thereon areresponsive to a magnetic field generated by a current passing through aconductor. However, in other arrangements, the integrated circuits areused in magnetic field sensors, responsive to a magnetic field externalto the integrated circuits. In still other arrangements, the integratedcircuits are used in proximity sensors, responsive to a magnetic fieldassociated with a moving ferrous object, or other soft magneticmaterial, for example, a rotating gear. In still other arrangements, theintegrated circuits are used in proximity sensors, responsive to amagnetic field generated by a moving permanent magnet, or hard magneticobject. In still other arrangements, the integrated circuits are used inisolators, responsive to a pulse signal in a conductor or coil.

The integrated circuits described above in conjunction with FIGS. 1, 1A,2, 2A, 3, 3A, 4, 4A, 5 and 5A are described as having two magnetic fieldsensing elements disposed on two substrates. However, in otherembodiments, instead of having two substrates, an integrated circuit canhave but one substrate, wherein the doping, and/or material of the twomagnetic field sensing elements are different. For example, in someembodiments, a region of a single Si substrate can be implanted with Geto create a SiGe Hall effect element, while a separate Si Hall effectelement can be formed elsewhere on the same substrate. With thesearrangements, the two magnetic field sensing elements can have differentsensitivities or can have the same sensitivity.

Described above in conjunction with FIGS. 1, 1A, 2, 2A, 3, 3A, 4, 4A, 5,and 5A, electronic components 18, 56, 118, 158, and 220, respectively,can be disposed on surfaces of respective substrates. The electroniccomponents can be comprised of circuits described in U.S. patentapplication Ser. No. 11/336,602, filed on Jan. 20, 2006, entitled“Current Sensor,” having inventors Michael C. Doogue, Vijay Mangtani,and William P. Taylor, which application is incorporated by reference inits entirety.

All references cited herein are hereby incorporated herein by referencein their entirety.

Having described preferred embodiments of the invention, it will nowbecome apparent to one of ordinary skill in the art that otherembodiments incorporating their concepts may be used. It is felttherefore that these embodiments should not be limited to disclosedembodiments, but rather should be limited only by the spirit and scopeof the appended claims.

What is claimed is:
 1. An integrated circuit, comprising: a lead frame;a first substrate having first and second opposing surfaces, wherein thefirst substrate is coupled to the lead frame such that the secondsurface of the first substrate is above the lead frame and the firstsurface of the first substrate is above the second surface of the firstsubstrate; a second substrate having first and second opposing surfaces,wherein the second substrate is coupled to the lead frame such that thesecond surface of the second substrate is above the lead frame and thefirst surface of the second substrate is above the second surface of thesecond substrate; an electronic component disposed on the first surfaceof the first substrate; a first magnetic field sensing element disposedon the first surface of the second substrate; and a second magneticfield sensing element disposed on the first surface of the firstsubstrate, wherein the first magnetic field sensing element provides afirst sensitivity to a magnetic field, wherein the second magnetic fieldsensing element provides a second different sensitivity to the magneticfield, and wherein the integrated circuit is configured to provide afirst operating range responsive to the first magnetic field sensingelement and a second different operating range responsive to the secondmagnetic field sensing element.
 2. The integrated circuit of claim 1,further comprising a conductor, wherein the integrated circuit isadapted to be responsive to magnetic field generated by a currentpassing through the conductor.
 3. The integrated circuit of claim 1,further including a flux concentrator disposed proximate to at least oneof the first magnetic field sensing element or the second magnetic fieldsensing element.
 4. The integrated circuit of claim 1, wherein the firstsubstrate is comprised of a selected one of Si, GaAs, InP, InSb, InGaAs,InGaAsP, Site, ceramic, or glass and the second substrate is comprisedof a selected one of Si, GaAs, InP, InSb, InGaAs, InGaAsP, Site,ceramic, or glass.
 5. The integrated circuit of claim 1, wherein thefirst surface of the second substrate is coupled to the first surface ofthe first substrate with a wire bond.
 6. The integrated circuit of claim5, further including at least one flux concentrator disposed proximateto at least one of the first magnetic field sensing element or thesecond magnetic field sensing element.
 7. The integrated circuit ofclaim 1, wherein the lead frame further comprises a plurality of leads,wherein at least two of the plurality of leads are coupled to form acurrent conductor portion, wherein the current conductor portion isdisposed proximate to the second substrate, and wherein the integratedcircuit is responsive to a current flowing through the current conductorportion.
 8. The integrated circuit of claim 1, further comprising: acurrent conductor disposed proximate to the second substrate; and a fluxconcentrator shaped so that a first portion of the flux concentrator isdisposed under the lead frame and a second portion of the fluxconcentrator is disposed above the first surface of the secondsubstrate.
 9. The integrated circuit of claim 1, wherein the first andsecond magnetic field sensing elements are different types of magneticfield sensing elements.